1. Field of the Invention
The present inventions relate generally to treatment of vertebral discs in the lumbar, cervical, or thoracic spine.
2. Description of the Related Art
The disc performs the role of absorbing mechanical loads while allowing for constrained flexibility of the spine. The vertebral tissue forming the disc includes a soft, central nucleus pulposus (NP) surrounded by a tough, woven annulus fibrosis (AF) and superior and inferior endplates. Herniation is a result of a weakening in the AF. Symptomatic herniations occur when weakness in the AF allows the NP to bulge or leak, for example, toward the spinal cord and major nerve roots. The most common resulting symptoms are pain radiating along a nerve and low back pain, both of which can be crippling for the patient.
Discectomy has been the most common surgical procedure for treating vertebral disc herniation. This procedure involves removal of disc materials impinging on the nerve roots or spinal cord external to the disc. Depending on the surgeon's preference, varying amounts of NP may also be removed from within the disc space either through the herniation site or through an incision in the AF. This removal of extra NP is commonly done to minimize the risk of recurrent herniation.